[14C]glucosamine incorporation into intestinal glycoproteins by calf intestinal epithelium in organ culture.

The uptake and incorporation of [14C]glucosamine into secreted intestinal glycoproteins was examined in the calf intestinal mucosa and isolated epithelial cells, using an organ culture system. Incorporation varied with the area of the intestine, ie duodenum greater than jejunum greater than ileum. Secreted glycoproteins were examined after 3 and 24 hours in organ culture. Initially, a glycoprotein approximately 68,000 molecular weight (mol wt) was secreted by all areas of the intestine. This was followed by the appearance of a larger glycoprotein 10(6) to 10(7) mol wt. Enzymatic cleavage of jejunal brush borders released a glycocalyx glycoprotein similar in size to the secreted large mol wt glycoprotein. These similarities in mol wt are only suggestive evidence that the 2 large glycoproteins are the same. This procedure allows for the study of the maturation and development of a poorly understood component of the intestinal epithelial cell which has a wide range of functional considerations.